1. Field of the Invention:
The present invention relates to a rotary shear installed in a corrugating machine for performing slotting work or cutting work upon a continuously traveling corrugated cardboard web nearly at right angles thereto.
2. Description of the Prior Art:
One example of a rotary shear in the prior art is illustrated in FIGS. 4 to 7. The rotary shear is an apparatus for cutting a corrugated cardboard web 17 which has been manufactured continuously in a corrugating machine or performing slotting work thereto along the widthwise direction of the web. The prior art rotary shear mainly operates at the time of order change and it functions to deal with switching of setting such as width change of trims 21a and 21b or sheet 21a-e.
A description of the general construction and function of a rotary shear in the prior art will be disclosed as follows. As shown in FIGS. 4(a) and (b), a knife cylinder 2 having a knife 1 fixedly secured thereto has its opposite ends pivotably supported from frames 4a and 4b, resting on floor FL, erected at the opposite width ends of the apparatus via bearings 3a and 3b, respectively. A shaft 6 is connected via an electromagnetic clutch brake 5 to an outer most end of the knife cylinder 2. A pulley 7 is mounted to shaft 6 which is coupled to a pulley 10 fixedly secured to a line shaft 8 or a shaft 8 of a motor 9 serving as an independent drive unit, via an endless synchronizing bell 11 wound therearound.
As further shown in FIGS. 4(a) and (b), an anvil cylinder 22 has its opposite ends pivotably supported from the frames 4a and 4b, respectively, via bearings 23a and 23b in parallel to the above-described knife cylinder 2. To one end of the anvil cylinder 22 is fixedly secured a pulley 24, which is coupled to a pulley 27 on a shaft 26 pivotably supported from the frame 4a via a belt 25. In addition, the above-mentioned shaft 26 is connected to an indexing motor 29 via an electromagnetic clutch brake 28. Reference numeral 12 designates an endless elastic body belt, which comes into slide contact with the outer circumferential surfaces of the knife cylinder 2 and the anvil cylinder 22, and is wound around a plurality of rolls 14 having their opposite shaft ends pivotably supported from the frames 4a and 4b. It is to be noted that the width of the above-mentioned belt 12 is made equal to or somewhat broader than that of the knife 1 on the knife cylinder 2, and the arrangement is such that the belt 12 can travel at a predetermined speed (a traveling speed of the corrugated PG,4 cardboard web 17) by making a gear 15 provided at a shaft end of the roll 14 mesh with a gear 16 fixedly secured to the shaft 8 of the driving motor 9. The surface of the above-mentioned anvil cylinder 22 has a configuration shown in FIGS. 5 and 6 in which a central portion of an elastic body 30 is removed on a part of the circumferential surface. The width of the removed part is successively decreased from a portion S extending over the entire width up to a predetermined dimension S.sub.o. A step (a recess and a ridge) is thus formed.
Accordingly, by variably setting the phase relationship between the knife 1 of the knife cylinder 2 and the anvil cylinder 22, two kinds of cutting works become possible, as shown in FIG. 7. More particularly, if the anvil cylinder 22 is engaged with the knife 1 at a position A in FIG. 6, then cutting over the entire width is possible. If the anvil cylinder 22 is engaged with the knife 1 at a position B in the same figure, then at the opposite width end portions of the corrugated cardboard web 17, slits (slots) having a length corresponding to a dimension P.sub.o in FIG. 6 can be formed. It is to be noted that in FIG. 6, the portion corresponding to a dimension P is a recessed portion formed on the cylindrical surface of the anvil cylinder 22. Accordingly, in this interval a pinching force (shearing force) between the knife 1 and the anvil cylinder 22 would not be generated, and so, cutting cannot be done. In addition, by appropriately variably setting the position B where the anvil cylinder 22 is engaged with the knife 1, the rotary shear of the illustrated type can machine slots having an arbitrary length of from zero to a maximum (W-S.sub.o)/2 at the opposite width ends of the corrugated cardboard web 17.
The operation of the rotary shear as shown in FIG. 4 will be described as follows. As initial setting of the rotary shear, at first the electromagnetic clutch brake 28 is connected, then the anvil cylinder 22 is rotated by driving the indexing motor 29 and a phase to be engaged with the knife 1 is set (indexed), and under that condition, the brake of the above-mentioned clutch brake 28 is actuated and thereby the anvil cylinder 22 is held at a fixed position.
Subsequently, the phase of the knife 1 is matched to the traveling corrugated cardboard web 17, and the electromagnetic clutch brake 5 is connected. The rotational behavior of the knife cylinder 2 is such that it can be rotated or stopped at a predetermined timing by operating (connecting or disconnecting) the electromagnetic clutch brake 5.
FIG. 9 is a schematic side view of a slitter-scorer positioned in the next stage, and FIG. 8 is a schematic plan view depicted at a position corresponding vertically to FIG. 9 as viewed on the same sheet of drawing for illustrating a machined condition of the corrugated cardboard web. A slitter-scorer illustrated generally by reference numerals Pa and Pb, is an apparatus for machining predetermined score lines K and slitting slots S on a traveling corrugated cardboard web 17 as shown in FIG. 8 by means of equipped scoring rolls 31a and 31b and slitter knives 32a and 32b, and by appropriately selecting a corrugated cardboard web width W in relation to a necessitated product sheet width W.sub.o. Accordingly, production of a plurality of sheets (multiple sheet production) can be done simultaneously (FIG. 8 illustrates the case of two-sheet production).
In addition, in order to reduce time for resetting necessitated by an order change, two slitter-scorers P.sub.a and P.sub.b are installed and aligned in the traveling direction of the sheets. It is to be noted that the entire width W of the above-described corrugated cardboard web to be produced was set somewhat broader than the width W.sub.o to be used as product sheets, and the opposite width end portions where faults, e.g. displacement upon sticking of the original paper sheets, squeezing-out of paste and the like are liable to occur, are cut in a belt shape, and are sucked into respective trim ducts 33 as trims (broke wastes) 21(a)-(e) and processed. The rotary shear in the prior art was operated as a trim shear to be used for cutting the tip ends of the trims 21b on the side of a new order, which was necessitated mainly upon switching the slitter-scorers Pa and Pb according to order change, that is, upon change of processing of the trims 21 which are formed depending upon a width W of the corrugated cardboard web being produced and a width Wo of the product sheets.
Next, changing the setting of a rotary shear in the prior art device is described as follows. A trimming position resulting from an order change is transmitted as a signal from an order change system controller, not shown. Various settings corresponding to a new order are carried out in the slitter-scorer P.sub.b, under a stand-by position, besides position setting of a trim duct 33b. At the same time, a relative angular position of the anvil cylinder 22 in a trim cutting device (rotary shear) is set with respect to position of the knife 1 so as to set slitting lengths at the opposite width ends of the corrugated cardboard web corresponding to the new order.
Then, the knife cylinder 2 and the elastic body belt 12 are rotated in the opposite directions at a predetermined timing matched with passage of the traveling corrugated cardboard web 17, and trim cutting notches are formed at the desired positions. Next, the above-mentioned notched positions are transferred to the slitter-scorer P.sub.b under a stand-by condition. The scoring rolls 31b, set at a predetermined position, are then meshed followed by the meshing of the slitter knives 32b, operate on the cardboard web according to the new order. On the other hand, the slitter-scorer P.sub.a works according to the old order. At a predetermined timing, when the leading end of the corrugated cardboard sheet according to the new order arrives, the engagements of the scoring rolls 31a and the slitter knives 32a are sequentially released. In addition, new trim 21b produced from the corrugated cardboard web 17 according to the new order are respectively sucked and conveyed by a pair of newly set trim ducts 33b, and are processed after they have been shredded by a cutter-blower 34 provided in the passageway.
The rotary shear in the prior art was constructed and operated in the above-described manner, and it had only two kinds of functions: slitting by an arbitrary length at the opposite width ends of a traveling corrugated cardboard web; or perfectly cutting the web over its entire width. Accordingly, in the setting for two-sheet production as shown in FIG. 8, a specification can be switched stably only under a limited condition such that only a trim width at the width ends is changed as a result of order change. In other words, a sheet separating slit slot has a continuous shape, and even if a sheet separating slit slot should become discontinuous as a result of change of a sheet width, cut lengths of the two sheets traveling in parallel are the same, or that only one kind of sheets are produced from a single web, though not shown.
However, in the case of changing a specification according to an order change, it occurs frequently that not only dimensions in the widthwise direction of sheets 20 are changed, but also cut lengths LT and LD of two sheets traveling in parallel are also arbitrarily changed as shown in FIG. 3. In two-sheet production for producing two kinds of sheets in parallel from a single corrugated cardboard sheet, as in the case where cut lengths of the sheets traveling in parallel are different from each other, a traveling route of a sheet on one side would be changed to be transferred respectively to different rotary drum shears 35a and 35b and cut into predetermined lengths at a cut-off D in the downstream stage. Accordingly, in the case where a specification has been changed, for example, as illustrated in FIG. 3, a discontinuous portion X would remain in the central slitting slot, and so, upon change of the traveling route (separation to upper and lower routes) at the cut-off D in the downstream stage in which is executed in the case where the lengths of the above-mentioned sheets traveling in parallel are different from each other, troubles would frequently occur such that not only the above-mentioned discontinuous portion is broken and becomes unacceptable paper sheets, but also the broken pieces of paper sheets are caught by downstream conveyor means (feed rolls) resulting in jam-up.
For the above-mentioned reasons, in the heretofore known rotary shear, in the case where the position of the sheet separating slitting slot is changed, upon order change, the method was employed of once cutting and separating the front and rear corrugated cardboard webs over the entire width and thereby avoiding damage to the sheets occurring at the above-mentioned discontinuous portion X. However, this method has the shortcoming in that restriction of the trailing end of the old order sheet and the leading end of the new order sheet would become free temporarily resulting in a zig-zag motion of the sheets 20 and variation of a conveying speed would arise. Consequently, the precision of the cutting length and the like would become unreliable, and it would become a principal cause of various troubles which may arise during the period before the sheet traveling condition becomes stable.
In summary, the above-described rotary shear in the prior art could perform only two kinds of cutting work: of machining slots in the widthwise direction of a sheet at the opposite width ends of a corrugated cardboard web; or perfectly cutting the web over the entire width of the sheet. Accordingly, the rotary shear was stable with stably under a limited condition such as where only trim widths are changed according to an order change. However, in multiple-sheet production, for instance, two kinds (a plurality of kinds) of sheets from a single corrugated cardboard sheet are created such as where widths of the sheets are changed as a result of order change and also where cut sheet lengths are different. There was a disadvantage with this operation in that at the changing point between the new and old orders, the slitting position would be displaced in the widthwise direction of the sheet, resulting in a discontinuous portion. Hence, the sheets would broken due to separation of the sheet traveling routes to the upper and lower routes at the cut-off in the subsequent stage, creating unacceptable paper sheets. Furthermore, it became a principal cause of various problems such as where broken pieces of the paper sheets would block the gap between conveyor rolls in the subsequent stage and result in jam-up or the like.
In addition, problems would result where the sheet is perfectly cut in the widthwise direction at the portion of the order change. As a counter-measure for the above-mentioned problem, although the disadvantages of breaking at the slitting portion and the like are eliminated, the trailing end of the old order sheet and the leading end of the new order sheet would become free, and the conveying condition would become unstable. Consequently, problems would arise resulting from the occurrence of zig-zag traveling or a traveling speed (length) variations, resulting in deterioration of precision in a cut length at the cut-off in the subsequent stage.